thE purposE oF thE pAssAgE is to ______.
A．AnAlyzE thE possiBlE CAusAl links BEtwEEn tiBEtAn ECology AnD soCiEty
B．DEsCriBE thE soCiAl orgAnizAtion oF typiCAl tiBEtAn villAgEs
C．DEsCriBE tiBEtAn FAunA AnD FlorA
D．AnAlyzE thE mystErious oF thE suDDEn AppEArAnCE oF thE himAlAyAs